<template>
  <div class="nav-bar" :class="{'is_fixed':isFixed}">
      <div class="container">
          <div class="pro-title">
              {{title}}
          </div>
          <div class="pro-param">
              <a href="javascript:;">概述</a><span>|</span>
              <a href="javascript:;">参数</a><span>|</span>
              <a href="javascript:;">用户评价</a>
              <slot name='buy'></slot>
          </div>
      </div>
  </div>
</template>

<script>
export default {
    name:'nav-bar',
    data() {
        return {
            isFixed:false
        }
    },
    mounted(){
        window.addEventListener('scroll',this.initHeight)
        // 吸顶功能
        // 监听页面滚动事件,当页面滚动的时候调用this.innitHeight方法
    },
    methods: {
        initHeight(){
            //页面滚动兼容写法
            let docScrollTop = document.documentElement.scrollTop || document.body.scrollTop;
            this.isFixed=docScrollTop>152?true:false
            // {'is_fixed':isfixed}通过true||false动态绑定css样式,实现效果,强大之处
        }
    },
    destroyed() {  //已完全销毁
        window.removeEventListener('scroll',this.initHeight,false)
        
    },
    props: ['title'],
}
</script>

<style lang="scss" scoped>
@import './../assets/scss/config.scss';
@import './../assets/scss/mixin.scss';

.nav-bar{
    height: 70px;
    line-height: 70px;
    border-top: 1px solid $colorH;
    z-index: 20 ;
    &.is_fixed{
        position: fixed;
        top: 0;
        width: 100%;
        background-color: $colorG;
        box-shadow: 0 5px 5px $colorE;
    }
    .container{
        @include flex();
        .pro-title{
            font-size:$fontH;
            color: $colorB;
            font-weight: bold;
            
        }
        .pro-param{
            font-size: $fontJ;
            a{
                color: $colorC;
                
            }
            span{
                margin: 0 10px;
            }
        }
    }
}
</style>